Precision paper take-up device for high speed web feed printer

ABSTRACT

A precision paper take-up device for a high-speed web feed printer, including a web storage reel, a normally energized motor for driving the reel in a take-up direction, a tensioning bail engaging the web ahead of the reel, and a resilient bias mechanism normally maintaining the bail in a home position. When the printer advances the web, producing slack in the web, the motor rotates the reel; the abrupt tightening of the web over the bail overcomes the bias and the bail moves away from its home position, de-energizing the motor. The bias on the bail pulls a limited length of the web back off the reel, until the bail reaches its home position, again energizing the motor and restoring equlibrium until the next advance of paper from the printer.

Ilnited States Eatent 1191 Kranz PRECISION PAPER TAKE-UP DEVICE FOR HIGH SPEED WEB FEED PRINTER [75] Inventor: Raymond E. Kranz, Mount Prospect, Ill. [73] Assignee: Extel Corporation, Chicago, lll.' [22] 'Filed: Sept. 13, 1972 21 Appl. N6; 288,486

52 u.'s. c1. 242/755, 242/673 R [51 1111.01 B65h 17/02, B65h 25/22 [58 Field 61 Search 242/7551, 75.3, 75.5,

- 242/67.l R, 189, 75, 67.3 R, 190

[56] References Cited UNITED STATES PATENTS 1,998,453 4/1935 Foster et al 242/189 2,262,032 11/1941 MOOIC 242/753 2,3l8,3l6 5/1943 Lawrence 242/753 x 3,019,999 2/1962 Schiff 242/7551 3,495,784 2/1970 Bradlee 242/755 3,679,149 7/1972 Ottavan 242/755 Primary Examiner-John W. Huckert Assistant Examiner-John M. Jillions Attorney, Agent, or Firm-Kinzer, Plyer, Dorn & McEachran [57] ABSTRACT A precision paper take-up device for a high-speed web feed printer, including a web storage reel, a normally energized motor for driving the reel in a take-up direction, a tensioning bail engaging the web ahead of the reel, and a resilient bias mechanism normally mainv taining the bail in a home position. When the printer advances the web, producing slack in the web, the motor rotates the reel; the abrupt tightening of the web over the bail overcomes the bias and the bail moves away from its home position, de-energizing the motor. The bias on the bail pulls a limited length of the web back off the reel, until the bail reaches its home position, again energizing the motor and restoring equlibrium until the next advance of paper from the printer.

2 Claims, 7, Drawing Figures PATENTEB UEC3 I I974 sum 20F 2 POWE R SUP PLY PRECISION PAPER TAKE-UP DEVICE FOR HIGH SPEED WEB FEED PRINTER BACKGROUND OF THE INVENTION There are a variety of different types of highspeed printer in which the printed information is produced upon an elongated paper web rather than on individual sheets. A particularly efficient and effective printer of this kind is the dot matrix printer described and claimed in Zenner and Kranz U.S. Pat. No. 3,670,861. In a printer of this general kind, the web is advanced by a short line increment during a brief time interval constituting a fractional part of the time required to return the printer carriage to begin a new line of characters. Printing is resumed as rapidly as possible, once the carriage return operation has been completed.

In many applications, particularly where the printer is used only intermittently or is subject to frequent attention from an operator who strips away the printed portion of the web, little or no difficulty is encountered in storing the printed portion of the web as it is fed out of the printer. In other applications, however, it may be necessary or desirable to store the printed paper web in substantially continuous and uninterrupted form for record purposes. The addition of a take-up reel or other web storage device to a high-speed printer of the kind under discussion can present substantial problems and may have an appreciable adverse effect upon operation of the printer itself.

Perhaps the simplest form of take-up device for a web feed printer is a continuously biased take-up reel. However, if the take-up reel applies substantial tension to the web at the time the web is advanced through the printer in a line feed operation, skewing or other displacement of the web can occur in the printer, which may lead to an appreciable misalignment of the printing. This effect, sometimes referred to as fpaper drift, occurs because the printer requires the maintenance of a balance between the forces on the paper entering the printer and the forces applied to the web as it passes through and is advanced beyond the printing area, a balance that is extremely difficult to maintain if there is a substantial take-up tension on the paper web during the line-feed operation. Stated differently, the forces tending to hold the paper on center in the printer must be greater than the forces tending to twist the paper or slide it off center at all times.

The braking of a paper take-up device for a highspeed printer also tends to create paper drift in the printer, with resultant deterioration in the quality of the imprinted material. That is, the paper take-up device must provide some means for absorbing the energy involved in stopping the movement of the take-up reel, once the line-feed operation of the printer is completed. Effective and rapid absorption of this energy is also. necessary because a heavy pull on the paper web, occurring after completion of a line-feed operation, may cause substantial distortion in the printed copy.

Many of these problems can be overcome by specific design of the printer itself to accommodate a paper take-up mechanism. However, this entails matching the operating characteristics of the take-up device to those of the printer, and may require the use of special construction in the printer. This is particularly undesirable if a given type of printer is being used in some instances with a take-up device and in others with no take-up device.

SUMMARY OF THE INVENTION It is an object of the invention, therefore, to provide i new and improved precision paper take-up device for a high-speed web feed printer which effectively allows for a rapid, free advance of paper from the printer, with the take-up operation applying only minimum tension to the web during a line-feed operation of the printer.

Another object of the invention is to provide a new and improved precision paper take-up device for a high-speed web feed printer that can be utilized on printers of varying construction without requiring modification of the printer and without disturbing the printer operation. v

A specific object of the invention is to provide a new and improved precision paper take-up device for a high-speed web feed printer that is simple and economical in construction and that is self-contained, requiring no electrical or mechanical control connections to the printer.

Accordingly, the invention pertains to a precision take-up device for a high-speed printer of the kind utilizing a web as a record medium and advancing the web from the printer in intermittent line-feed steps. The take-up device comprises a reel for storing a paper web and a bail which engages the paper web at a location adjacent the reel, the bail being pivotally movable between a home position and an actuated position. A normally energized electric motor is operatively connected to the reel and applies a torque to the reel tending to rotate the reel in a take-up direction to wind the web on the reel and maintain the web under limited tension. The take-up device includes sensing means, responsive to movement of the bail, for de-energizing the motor whenever the bail moves from its home position toward its actuated position. Bias means are included in the device, biasing the bail toward its actuated position in response to an abrupt engagement of the web with the bail during a take-up movement of the web. The force applied to the bail by the bias means is sufficient to pull a limited portion of the web back off of the reel, with the motor de-energized, thereby returning the bail to its home position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a precision paper takeup device, constructed in accordance with one embodiment of the present invention, mounted upon a highspeed web feed printer;

FIG. 2 is a side elevation view of the paper take-up device shown in FIG. I;

FIG. 2A is a detail view illustrating an alternate operating condition for the mechanism as shown in FIG. 2;

FIG. 3 is a plan view of the precision paper take-up device of FIG. 1;

FIG. I is a front elevation view of the paper take-up device;

FIG. 5 is a detail elevation view of a retainer mechanism incorporated in the paper take-up device; and

FIG. 6 is a schematic illustration of the operating circuit for the motor of the paper take-up device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a high-speed web feed printer 10 comprising a base 11 upon which a printing mechanism 12 is mounted. The printer mechanism 12 is enclosed in a housing 13 that includes a hinged cover 14, cover 14 being shown in open position to afford a view of some of the components of the printing mechanism 12. The control circuits for printer 10 are mounted within an enclosure that constitutes a rearward extension 15 of base 11.

A paper supply roll 16 is mounted in brackets 17 on the rear housing 15 of printer 10. A paper web 18 extends from supply roll 16 around a roller platen 19 that is a part of the printing mechanism 12. A spring-biased bail 21 holds the paper web 18 on platen 19; additional guides 22 are provided to retain the paper web 18 in centered relation on the roller platen. Printing mechanism 12 includes a line-feed apparatus (not shown) for rotating the roller platen 19 through relatively short angular increments to effect a line-feed advance of the paper web. The remainder of printing mechanism 12 has been omitted from FIG. 1 because it is not essential to explanation or understanding of the present invention. Printing mechanism 12 may include a dot matrix printer head and carriage of the kind described in the aforementioned Zenner and Kranz US. Pat. No. 3,670,861; on the other hand, an entirely different mechanism for applying a printed impression to web 18 may be incorporated in printer 10 if desired.

A precision paper take-up device 30, constructed in accordance with the present invention, is mounted upon the rear base extension 15 of printer 10. Take-up device 30 comprises a frame of U-shaped configuration, including a horizontal base plate 31 and two vertically extending side frame members or arms 32 and 33. The frame may also include additional bracing, such as the transverse rod 40.

A reel 34 for storing the paper web 18 as the web is advanced from printer lll is mounted between the side frame members 31 and 32 of take-up device 30. Reel 34 includes two reel hubs 35 and 36 (FIGS. 3 and 4). Two web retainer discs 37 and 38 are mounted upon hubs 35 and 36, respectively. A plurality of rods 39 are incorporated in reel 34; the rods 39 form the central portion of reel 34, joining the two hubs 35 and 36.

An electric motor 41, which may comprise a split phase gearmotor of conventional construction, is mounted on the side frame member 32 of take-up device 30. The output shaft 42 of motor 41 is operatively connected to reel hub 36 so that the reel hub is supported upon the motor shaft 42 and rotates in response to operation of the motor. At the opposite side of reel 34, hub 35 is journalled on and supported by the end of a cantilever reel support shaft 44 which is aligned coaxially with motor shaft 42. The reel support shaft 44 is journalled in and supported by a bearing 47 mounted upon the side frame member 33, bearing 47 allowing axial movement of shaft 44. A shoulder element 43 is affixed to shaft 44, adjacent hub 35, and a spring 45 is mounted on shaft 44 between shoulder 43 and the end of bearing 47, biasing shoulder 43 toward hub 35. The

end of shaft 44 remote from hub 35 extends through an aperture in frame member 33, and a knob 46 is affixed to the outer end of the shaft.

The precision paper takeup device 30 further comprises a bail 51 that extends transversely across the upper front end of the paper take-up device, adjacent reel 34, shown in FIGS. 2, 3 and 4. Bail 51 engages the paper web 18. The bail is pivotally mounted upon two pivot pins 52 and 53 which are mounted on the side frame members 32 and 33, respectively. The end of bail 51 adjacent-pivot pin 52 includes a downwardly projecting crank arm 54. The intermediate portion of the crank arm 54 connected to one end of a bias spring 55, the otherend of spring 55 being anchored to a pin 56 mounted on side frame member 32 (FIG. 2).

The lower end of the bail crank arm 54 terminates in a contact element 57. In the home position for bail 51, as illustrated in FIG. 2, contact element 57 engages the actuator element 58 of a sensing switch 59. Sensing switch '59 and a main on-off switch 61 constitute the only controls necessary for motor 41. The operating circuit for motor 41 is illustrated in FIG. 6. As shown therein, the two switches 59 and 61 are connected in a series energizing circuit for motor 41, the energizing circuit connecting the motor to a suitable power supply. The power supply may constitute a power outlet provided on printer 10, or may comprise an independent external power source. In any event, there is no electrical control connection from printer 10 to takeup device 30, nor is there any mechanical control linkage between the printer and the take-up device.

The end of bail 51 adjacent pivot pin 53 comprises a downwardly extending crank arm 64 terminating in a bail stop member 65. As best shown in FIG. 5, the bail stop member 65 is aligned with a fixed stop member 66 that is mounted upon side frame member 33. Preferably, an adjustable mounting is provided for the fixed stop member 66. In the illustrated construction, the fixed stop member 66 comprises a permanent magnet and the bail stop member 65 is formed of magnetizable material to afford a magnetic latch keeper. The two stop members 65 and 66 comprise a retainer mechanism for releasably retaining the bail in its home position, the positionillustrated in FIG. 2. It is not essential that a magnetic retainer mechanism be employed; a resilient friction retainer or other readily releasable retainer mechanism can be utilized if desired.

When a new paper supply roll 16 is installed in printer 10 (FIG. 1) the paper web is threaded through the printer around platen 19. A substantial length of the paper web 18 is advanced through the printer and is guided over bail 51 The end of web 18 is threaded between any two of the reel rods 39. Pick-up device 30 is then ready for operation and the main control switch 61 is closed (FIGS. 2, 3, 4 and 6). I

During printing of a line of characters in printer 10, take-up device 30 remains in the home condition illustrated in FIG. 2. For this operating condition, the winder motor 41 is energized but is held in stalled condition. The paper web 18 is maintained in tension, extending across bail 51 and into reel 34. The bias means comprising spring 55 (FIG. 2) and retainer mechanism 68(FIG. 5) holds bail 51 in its home position and prevents rotation of the bail.

When the high speed printer 10 completes a line of characters (e.g., data line 22, FIG. 1), and is ready to initiate printing of a new line, platen 19 rotates to advance a short length of the paper web 18 outwardly of the printer in the direction of arrow A (FIGS. 1 and 2). The advance of web 18 from printer causes the web to become slack. Because motor 41 is already energized, the motor starts to rotate reel 34 in a take-up direction, indicated by arrow B in FIG. 2, to wind the slack portion of the web onto the take-up reel. The take-up rotation of reel 34 does not apply appreciable tension to web 18 during the time interval in which the line feed movement occurs in printer 11), due to the delay in reel rotation caused by the inertia of the takeup mechanism, particularly the inertia of reel 34 and motor 41.

As the take-up rotation of reel 34 continues, web 18 contacts bail 51. The force applied to bail 51 by web 18, which engages the bail rather abruptly is sufficient to disengage the magnetic retainer members 65 and 66, so that bail 51 is pivoted in a counterclockwise direction away from its home position (FIG. 2) toward the actuated position illustrated in FIG. 2A. The movement of bail 51 from its home position to its actuated position disengages the bail contact member 57 from the switch contact element 58, opening sensing switch 59 (FIGS. 2 and 2A). As a consequence, motor 41 is deenergized (FIG. 6).

With motor 41 de-energized, the spring loaded bail 51 absorbs the remaining inertia load of the take-up device 30 and reel 34 is braked to a stop. From the actuating position illustrated in FIG. 2A, with motor 41 deenergized, the bias spring 55 pulls bail 51 back to its home position, again applying limited tension to paper web 18. In returning bail 51 to its home position, spring 55 applies sufficient force to bail 51 to pull a limited length of web 18 back off of reel 34. As bail 51 reaches its home position, contact member 57 again engages the contact element 58 of sensing switch 59, completing the energizing circuit for motor 41 in preparation for the next take-up operation. The return movement to the home position is limited by the engagement of the magnetic retainer members, stop members 65 and 66 (FIG. 5), which are adjusted to determine the home position for the spring-loaded bail.

When reel 34 is full, or when it is desired to remove the stored web for some other reason, switch 61 is actuated to its off position and knob 46 is pulled outwardly of frame member 33, disengaging shaft 44 from reel hub 35. Reel 34 can then be moved a short distance away from motor shaft 42, and removed from take-up device 30. Hub 35 and disc 37 are readily disengageable from rods 39, since the rods are merely inserted in sockets in hub 35 (see FIG. 4). Accordingly, it is a simple matter to remove disc 37 and hub 35 from the reel and to pull the stored web from the rods 39. Reel 34 can then be quickly re-assembled and mounted in takeup device 30. Web 18 is again threaded into reel 34, around rods 39, switch 61 is thrown on, and device 30 is again in operation.

From the foregoing description, it will be apparent take-up device 30 acts rapidly and precisely to take up the slack in web 18 whenever a line feed advance of the web from printer 10 occurs. Because motor 41 is continuously energized, the take-up operation is initiated promptly each time web 18 advanced from the printer. However, the take-up device does not exert substantial tension on the paper web during the actual line feed operation, due to the inertia of reel 34 and the maintenance of bail 51 in its home'position at the beginning bias spring for bail 51, the energy-absorption operation being facilitated by shutting. off motor 41 in response to movement of the bail from its home position to its actuated position. The take-up reel 34 is brought to rest rapidly and effectively, with no bounce because bail 51 is latched in its home position, once returned to that position, by the retainer mechanism comprising the magnetic latch 68 for bail 51.

Reel 34 can be readily and rapidly removed from device 30, and the reel can be emptied and returned to the take-up device in a short time, so that only one reel is required. Take-up device 30 is relatively simple and inexpensive in construction and requires no control connection, either electrical or mechanical, to printer 10, so that no modification of the printer is necessary and the same printer can be used with or without the take-up device.

I claim:

1. A precision paper take-up device for a high speed printer utilizing a web as a record medium and advancing the web from the printer in intermittent steps, comprising:

a reel for storing a web;

a bail for engaging the web at a location adjacent the reel, the bail being pivotally movable between a home position and an actuated position;

a bail stop member on the bail;

a fixed stop member positioned in the path of the bail stop'member, the two stop members conjointly defining the home position for the bail;

a normally energized electric motor, operatively connected to the reel to apply a limited torque to the reel tending to rotate the reel in a take-up direction to wind the web on the reel and maintaining the web under limited tension;

sensing means, responsive to movement of the bail, for de-energizing the motor whenever tha bail moves from its home position toward its actuated position;

and bias means, comprising a spring connected to the bail, biasing the bail toward and tending to maintain the bail in its home position, but permitting movement of the bail toward its actuated position in response to an abrupt engagement of the web with the bail in a take-up movement of the web;

the bias means applying sufficient force to the bail to pull a limited portion of the web from the reel, with the motor de-energized, and return the bail to its home position, thereby again energizing the motor so that the motor is maintained energized continuously except for brief intervals when the bail is moved away from its home position as aforesaid;

the bias means further comprising a retainerdevice for releasably retaining the bail in its home position, preventing bouncing of the bail or reel on return of the bail to its home position.

2. A precision paper take-up device, according to claim 1, in which the retainer mechanism comprises a permanent magnet, mounted on one of the stop members, and in which the other stop member comprises a magnetic keeper element. 

1. A precision paper take-up device for a high speed printer utilizing a web as a record medium and advancing the web from the printer in intermittent steps, comprising: a reel for storing a web; a bail for engaging the web at a location adjacent the reel, the bail being pivotally movable between a home position and an actuated position; a bail stop member on the bail; a fixed stop member positioned in the path of the bail stop member, the two stop members conjointly defining the home position for the bail; a normally energized electric motor, Operatively connected to the reel to apply a limited torque to the reel tending to rotate the reel in a take-up direction to wind the web on the reel and maintaining the web under limited tension; sensing means, responsive to movement of the bail, for deenergizing the motor whenever tha bail moves from its home position toward its actuated position; and bias means, comprising a spring connected to the bail, biasing the bail toward and tending to maintain the bail in its home position, but permitting movement of the bail toward its actuated position in response to an abrupt engagement of the web with the bail in a take-up movement of the web; the bias means applying sufficient force to the bail to pull a limited portion of the web from the reel, with the motor deenergized, and return the bail to its home position, thereby again energizing the motor so that the motor is maintained energized continuously except for brief intervals when the bail is moved away from its home position as aforesaid; the bias means further comprising a retainer device for releasably retaining the bail in its home position, preventing bouncing of the bail or reel on return of the bail to its home position.
 2. A precision paper take-up device, according to claim 1, in which the retainer mechanism comprises a permanent magnet, mounted on one of the stop members, and in which the other stop member comprises a magnetic keeper element. 